Hydrogen generation system and fuel cell system having the same

ABSTRACT

A hydrogen generation system comprises are former  1  that contains a reforming catalyst, an evaporator  4  that supplies steam to the reformer  1 , a heater  3  that heats the reformer  1  and the evaporator  4 , a material feed portion  5  that feeds a feed material containing hydrocarbon compound to the reformer  1  through the evaporator  4 , and a water supply portion  6  that has a flow rate switch  6   a  and supplies water to the reformer  1  and the evaporator  4.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a hydrogen generation systemconfigured to reform a fuel comprising compound containing at leastcarbon and hydrogen as major component to generate a hydrogen gas. Moreparticularly, the present invention relates to a hydrogen generationsystem that operates uniquely in start, and a fuel cell system havingthe same.

[0003] 2. Related Art

[0004] One example of a method of generating a hydrogen-rich gas is asteam reforming method in which an organic compound based fuel and waterare reacted with each other using a reforming catalyst with heatexternally applied. In the steam reforming method, in order to react thewater with the fuel, the water needs to exist as steam in the reformingcatalyst.

[0005] In a plant-scale hydrogen generation system using the steamreforming method, typically, a steam supply portion comprised of aboiler or the like is provided outside of the system, and the steamgenerated in the steam supply portion and the fuel are supplied to areforming catalyst bed. On the other hand, in a small-scale hydrogengeneration system, typically, a steam supply portion is provided insideof the system and steam generated in the steam supply portion is used tocause steam reforming reaction to proceed. In a phosphoric acid fuelcell power generation system using a hydrogen gas as a fuel, which isone type of a distributed power generation system, steam is generatedusing heat resulting from operation of a fuel cell at a temperature of200 to 250° C., and is supplied to the hydrogen generation system.

[0006] During steady operation of the hydrogen generation system, sincethe reforming catalyst is subjected to a constant thermal load, changein its catalytic activity is easy to check. On the other hand, duringstart of the system, the thermal load varies with an elapse of time,which might significantly degrades the catalytic activity. Accordingly,for the purpose of protecting the catalytic activity of the reformingcatalyst to be used in steam reforming, it is desirable to supply thesteam to the reforming catalyst bed in advance. To this end, in thehydrogen generation system having the steam supply portion such as theboiler, the steam is first generated stably in the steam supply portionand an operation of a reformer of the system is then started. Meanwhile,in a fuel cell power generation system which is one type of thedistributed power generation system disclosed in Japanese Laid-OpenPatent Application Publication No. Hei. 5-275103, the system isinternally provided with a steam supply means, and an operation of areformer of the system is started while supplying steam generated in thesteam supply means to the reformer, using a nitrogen gas.

[0007] However, in the small-scale hydrogen generation system, forexample, a home cogeneration system using a polymer fuel cell, if thehydrogen generation system is used along with a steam supply unit usingan external heat source such as the boiler, energy efficiency, anoperating cost, and cost of the system are reduced. Since thesmall-scale hydrogen generation system has a heat source for supplyingheat required for reforming reaction, the heat derived from the heatsource is commonly used to generate the steam. For example, in thehydrogen generation system using a natural gas as a fuel, steamreforming reaction is adapted to proceed in a reforming catalyst bed ata temperature of 650 to 750° C. Also, in the system using anotherhydrocarbon based fuel, the reforming catalyst bed is heated to atemperature approximately equal to that in the system using the naturalgas. For the purpose of efficiently utilizing heat energy resulting fromreforming reaction conducted at this high temperature, a hydrogengeneration portion is generally configured to use heat resulting fromthe reforming reaction to generate steam. Thus, the hydrogen generationsystem provided with the steam generation portion allows effective useof the heat energy resulting from the reforming reaction during steadyoperation.

[0008] The hydrogen generation system for use in the home system needsto be adapted to operating conditions including frequent system startingand stopping operations, in contrast to the large-scale (e.g.,plant-scale) system. During start of the system, heat energy suppliedfrom the heat source is first used to heat the reforming catalyst and isthen used to generate steam in the steam generation portion. Thus, sincethe heat energy is used with priority to heat the reforming catalystduring start of the system, there is a possibility that sufficient steamis not generated in the steam generation portion and is not supplied tothe reforming catalyst at that time. As a result, depending on aconfiguration of the system or heating condition, the reforming catalystis heated excessively and is subjected to large thermal load, andthereby the catalytic activity of the catalyst is degraded.

SUMMARY OF THE INVENTION

[0009] The present invention has been developed in view of theabove-described problem, and an object of the present invention is toprovide a hydrogen generation system, which is capable of reducingthermal load applied on a reforming catalyst during start of the system,and of dealing with repeated starting and stopping operationssatisfactorily.

[0010] According to the present invention, there is provided a hydrogengeneration system comprising: a reformer for generating a reformed gasthat contains hydrogen by reforming reaction from a feed material andsteam using a reforming catalyst; an evaporator for evaporating waterinto the steam which is supplied to the reformer; a heater for heatingthe reformer and the evaporator for reforming and evaporation,respectively; a material feed portion for feeding the feed material tothe reformer directly or through the evaporator; a water supply portionfor supplying the water; a first water passage through which the wateris supplied from the water supply portion to the evaporator; and asecond water supply passage through which the water is supplied from thewater supply portion to the reformer.

[0011] In accordance with this configuration, the hydrogen generationsystem that conducts steam reforming of the feed material such as ahydrocarbon based fuel to generate the reformed gas containing hydrogenas a major component, has the first and second water supply passagesprovided to supply water to the evaporator and the reformer,respectively, and thereby, the steam can be supplied to the reformerduring start of the system. Therefore, it is possible to avoiddegradation of catalytic activity of the reforming catalyst in thereformer, which would be caused by deficiency of the steam in start ofthe system. As a result, water evaporation is optimized in operation ofthe system and the system can operate with increased energy useefficiency.

[0012] Upon starting supply of the feed material from the material feedportion to the reformer, the water may be supplied from the water supplyportion to the reformer through the second water supply passage, andafter an elapse of a predetermined time after starting the supply, thewater may be supplied from the water supply portion to the evaporatorthrough the first water supply passage, and the supply of the water tothe reformer may be stopped.

[0013] With this configuration, the water is not supplied to theevaporator whose temperature has not been sufficiently increased but isdirectly supplied to the reformer that has an increased temperaturesufficient to conduct water evaporation reaction and steam reformingreaction, while in a steady operation state after an elapse of apredetermined time, the water is supplied to the evaporator that has anincreased temperature sufficient to conduct the water evaporationreaction and the supply of the water to the reformer is stopped. Thus,during start of the system and steady operation of the system, the steamcan be supplied to the reformer smoothly and stably, and heat efficiencycan be increased.

[0014] The reformer may have a temperature measuring portion fordetecting a temperature of the reforming catalyst or a temperature of agas inside the reformer, and based on temperature information detectedby the reformer temperature measuring portion, supply of the feedmaterial from the material feed portion and supply of the water from thewater supply portion may be controlled.

[0015] With this configuration, since the supply of the water and thefeed material supplied to the reformer and the evaporator, can becontrolled based on the temperature of the reformer, it is possible toachieve a hydrogen generation system that can operate stably and gainincreased heat efficiency.

[0016] In the system, when the temperature detected by the reformertemperature measuring portion is larger than a preset reference value,the water may be supplied from the water supply portion to the reformerthrough the second water supply passage and the feed material may be fedfrom the material feed portion to the reformer.

[0017] With this configuration, since the feed material and the waterare reliably supplied to the reformer which has been heated sufficientlyto conduct steam reforming reaction, the steam reforming can beconducted smoothly without clogging in a flow passage or degradation ofcatalytic activity of the reforming catalyst inside the reformer.

[0018] In the system, when the temperature detected by the reformertemperature measuring portion is larger than a preset first referencevalue, the water may be supplied from the water supply portion to thereformer through the second water supply passage and the feed materialmay be fed from the material feed portion to the reformer, and when thetemperature detected by there former temperature measuring portion islarger than a preset second reference value larger than the firstreference value, the water may be supplied from the water supply portionto the evaporator through the first water supply passage and the supplyof the water to the reformer may be stopped.

[0019] With this configuration, since the feed material and the waterare reliably supplied to the reformer which has been heated sufficientlyto conduct reforming reaction and the steam reforming can be conductedsmoothly therein, and at the time when the evaporator has been heatedsufficiently to evaporate water, the water is supplied to theevaporator, where the water is evaporated into the steam. Therefore, thesteam can be supplied stably to the reformer and heat efficiency can beincreased.

[0020] The evaporator may have a temperature measuring portion fordetecting a temperature of the evaporator or a temperature of a gasinside the evaporator, and based on temperature information detected bythe evaporator temperature measuring portion, supply of the water fromthe water supply portion to the reformer and supply of the water fromthe water supply portion to the evaporator may be controlled.

[0021] With this configuration, since the water supply to the reformerand the evaporator can be controlled based on the temperature of theevaporator, it is possible to achieve a hydrogen generation system thatcan supply the steam stably and gain increased heat efficiency.

[0022] In the system, when the temperature detected by the evaporatortemperature measuring portion is smaller than a preset reference value,the water may be supplied from the water supply portion to the reformerthrough the second water supply passage, and when the temperaturedetected by the evaporator temperature measuring portion is larger thanthe reference value, the water may be supplied from the water supplyportion to the evaporator through the first water supply passage and thesupply of the water to the reformer may be stopped.

[0023] With this configuration, the water is reliably supplied to theevaporator that has been heated sufficiently to conduct waterevaporation reaction, the water evaporation can be conducted in theevaporator smoothly and the steam can be supplied stably.

[0024] The evaporator may have a heater for heating the evaporator. Theheater of the evaporator may be controlled based on a temperature of thereformer or a temperature of the evaporator. Specifically, when thetemperature of the reformer or the temperature of the evaporator issmaller than a preset reference value, the water may be supplied fromthe water supply portion to the reformer through the second water supplypassage and the heater of the evaporator is operated, and when thetemperature of the reformer or the temperature of the evaporator islarger than the reference value, the water may be supplied from thewater supply portion to the evaporator through the first water supplypassage and the operation of the heater of the evaporator may bestopped. Further, when the temperature of the reformer is larger than apreset first reference value, the feed material may be fed from thematerial feed portion to the reformer and the water may be supplied fromthe water supply portion to the reformer through the second water supplypassage, and the heater of the evaporator may be operated, and when thetemperature of the reformer is larger than a preset second referencevalue which is larger than the first reference value, the water may besupplied from the water supply portion to the evaporator through thefirst water supply passage and the supply of the water to the reformeris stopped, and the operation of the heater of the evaporator may bestopped.

[0025] The system may further comprise: a vaporizer for generating thesteam from the water, the steam generated in the vaporizer beingsupplied to at least one of the reformer and the evaporator. Thevaporizer may be controlled based on a temperature of the reformer or atemperature of the evaporator. Further, when the temperature of thereformer or the temperature of the evaporator is larger than a presetreference value, the water may be supplied from the water supply portionto the evaporator through the first water supply passage and theoperation of the vaporizer may be stopped. Moreover, when thetemperature of the reformer is larger than a preset first referencevalue, the feed material may be fed from the material feed portion tothe reformer, and the vaporizer may be operated to allow the steam to besupplied to the reformer, and when the temperature of the reformer islarger than a preset second reference value which is larger than thefirst reference value, the water may be supplied from the water supplyportion to the evaporator through the first water supply passage and theoperation of the vaporizer may be stopped.

[0026] With the above configuration, the provision of the heater of theevaporator or the vaporizer facilitates generation of the steam.Thereby, the steam can be supplied to the reformer more stably. Inaddition, by controlling the operation of the heater of the evaporatoror the operation of the vaporizer based on the temperature of thereformer or the temperature of the evaporator, the steam can be suppliedstably and the heat efficiency can be increased.

[0027] The evaporator may include: a first evaporator placed in contactwith the reformer so as to communicate with the reformer and connectedto the water supply portion at least through the second water supplypassage, the first evaporator being configured to evaporate the watersupplied to the reformer at least through the second water passage intosteam which is supplied to the reformer, and a second evaporatorconnected to the water supply portion through the first water supplypassage, the second evaporator being configured to evaporate the watersupplied from the water supply portion into the steam which is suppliedto the reformer.

[0028] With this configuration, since the steam generated in the firstevaporator is supplied to the reformer, the steam can be generated andsupplied more stably.

[0029] The water supply portion may have a water supply switch forswitching of water destination between the reformer and the evaporator.The water supply switch may be capable of adjusting a flow rate of thewater to be supplied to the reformer and a flow rate of the water to besupplied to the evaporator. In addition, the water supply switch may becapable of switching of the water supply passage between the first watersupply passage and the second water supply passage.

[0030] With this configuration, switching of water supply to thereformer and to the evaporator is easily achieved.

[0031] In the system, at a time when supply of the feed material to thereformer starts, at least one of the water and the steam may exist in atleast one of the reformer and to the evaporator.

[0032] With this configuration, since at the start of the system, thewater or the steam already exists in there former, the water evaporationreaction space of the evaporator, or the passage of the evaporator, thesteam can be supplied smoothly to the reformer.

[0033] According to the present invention, there is also provided a fuelcell system comprising: a hydrogen generation system including areformer for generating a reformed gas that contains hydrogen byreforming reaction from a feed material and steam using a reformingcatalyst; an evaporator for evaporating water into the steam which issupplied to the reformer; a heater for heating the reformer and theevaporator for reforming and evaporation, respectively; a material feedportion for feeding the feed material to the reformer directly orthrough the evaporator; a water supply portion for supplying the water;a first water passage through which the water is supplied from the watersupply portion to the evaporator; and a second water supply passagethrough which the water is supplied from the water supply portion to thereformer; and a fuel cell for generating a power using an oxidizingagent and hydrogen supplied from the hydrogen generation system.

[0034] With this configuration, since hydrogen can be supplied from thehydrogen generation system to the fuel cell stably and with high heatefficiency, highly-reliable and stable power generation can be carriedout with high heat efficiency.

[0035] The above and further objects and features of the invention willmore fully be apparent from the following detailed description withaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 is a view showing a configuration of a hydrogen generationsystem according to a first embodiment of the present invention;

[0037]FIG. 2 is a view showing a configuration of a hydrogen generationsystem according to a second embodiment of the present invention;

[0038]FIG. 3 is a view showing a configuration of a hydrogen generationsystem according to a third embodiment of the present invention;

[0039]FIG. 4 is a view showing a configuration of a hydrogen generationsystem according to a fourth embodiment of the present invention;

[0040]FIG. 5 is a schematic view showing a configuration of a vaporizerin the hydrogen generation system in FIG. 4;

[0041]FIGS. 6A and 6B are schematic views showing another configurationof the vaporizer of the hydrogen generation system in FIG. 4;

[0042]FIG. 7 is a view showing a detailed configuration of a reformeraccording to a fifth embodiment of the present invention; and

[0043]FIG. 8 is a schematic view showing a configuration of a fuel cellsystem comprising the hydrogen generation system in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Hereinafter, embodiments of the present invention will bedescribed with reference to the accompanying drawings. In theembodiments described below, a hydrogen generation system of the presentinvention is applied to a home power generation system using a fuelcell. The use of the hydrogen generation system of the present inventionis not intended to be limited to this.

[0045] (First Embodiment)

[0046]FIG. 1 is a view showing a configuration of a hydrogen generationsystem according to a first embodiment of the present invention.Referring now to FIG. 1, the hydrogen generation system comprises areformer 1, a heater 3, a material feed portion 5 for feeding a feedmaterial to the reformer 1, a water supply portion 6 for supplying waterto the reformer 1, an evaporator 4 for evaporating the water suppliedfrom the water supply portion 6 to generate steam, and a control portion7.

[0047] In this hydrogen generation system, the reformer 1 and theevaporator 4 are placed inside of a body 15, and the heater 3 forheating the reformer 1 and the evaporator 4 is placed below the body 15.The evaporator 4 is connected to the reformer 1 through a mixed materialsupply passage 16. A reformed gas passage 8 is connected to the reformer1 to allow a reformed gas obtained by steam reforming reaction to be ledfrom the reformer 1 to outside therethrough. The evaporator 4 isconnected to the material feed portion 5 provided outside of the body 15through a material feed passage 5 a and to the water supply portion 6through a supply passage 6 c. The water supply portion 6 is connected tothe reformer 1 through a supply passage 6 b. The material feed portion 5and the water supply portion 6 are respectively controlled by thecontrol portion 7.

[0048] In the reformer 1, steam reforming reaction is mainly conductedin such a manner that a feed material fed from the material feed portion5, for example, a feed material comprising compound containing at leastcarbon and hydrogen as major component, which is represented byhydrocarbon based compound, is steam-reformed using steam obtained byevaporating the water supplied from the water supply portion 6. Examplesof the hydrocarbon based compound are hydrocarbon component such as anatural gas, or a LPG (liquefied petroleum gas), alcohol component suchas methanol, or naphtha component. The reformer 1 has a reformingreaction portion configured to contain a reforming catalyst for causingthe reforming reaction to proceed, for example, a ruthenium catalystcarried on an alumina carrier. The detail of an internal structure ofthe reformer 1 will not be described and will not be shown here in.There former 1 is provided with a temperature measuring portion 2 formeasuring a temperature of an inside of the reformer 1. As used herein,the temperature of the reformer 1 refers to a temperature of thereforming catalyst or a temperature of a gas inside the reformer 1. Thetemperature measuring portion 2 has a thermocouple, a thermister, or thelike, and is suitably provided at a location and in an atmosphere wherethe temperature of the reformer 1 can be measured. The reformed gascontaining a hydrogen gas as major component, which is obtained by thesteam reforming reaction conducted in the reformer 1, is supplied to theoutside through the reformed gas passage 8. The hydrogen generationsystem may be configured such that a treating portion for treating thereformed gas according to a characteristic of an apparatus to which thereformed gas is supplied, is located downstream of the reformer 1 in aflow path of the reformed gas. For example, in a hydrogen generationsystem 150 that generates a hydrogen gas to be supplied to a fuel cell151 in a fuel cell system in FIG. 8, if the hydrogen gas to be suppliedto the fuel cell 151 contains carbon monoxide, then function of the fuelcell 151 is degraded, and it is therefore necessary to generate a gascontaining carbon monoxide with a low concentration. To this end, acarbon monoxide shifter 152 for reducing carbon monoxide contained inthe reformed gas, a carbon monoxide selective oxidation portion 153, andthe like, may be provided downstream of the reformer 1. In thisconfiguration, by using the hydrogen gas containing reduced carbonmonoxide and an oxidizing agent containing oxygen, the fuel cell 151 canstably generate a power.

[0049] The heater 3 mainly serves to supply heat required for steamreforming reaction to the reformer 1, and also supply heat to theevaporator 4 because of the configuration of the system. The reformer 1,which first receives the heat from the heater 3, is located on upstreamside, and the evaporator 4 is located on downstream side, in a flow pathof heat. The heater 3 has a flame burner that combusts part of the feedmaterial fed from the material feed portion 5, or an excess gas returnedfrom a destination to which the hydrogen gas obtained by the hydrogengeneration system was supplied(e.g., an off-gas derived from the fuelcell power generation system). The flame burner uses, for example, asirocco fan 3 a (its detail is not shown) for supplying combustion air.

[0050] The evaporator 4 is configured to evaporate the water suppliedfrom the water supply portion 6 into steam using the heat from theheater 3, and the resulting steam is mixed with the feed material fedfrom the material feed portion 5 and supplied to the reformer 1 througha mixed material supply passage 16. Here, the evaporator 4 is capable ofpreheating the feed material fed from the material feed portion 5 aswell as evaporating the water.

[0051] The material feed portion 5 serves to feed the feed material tothe reformer 1. Here, as the feed material, a natural gas is used.Although not shown, the material feed portion 5 has a booster forincreasing a supply pressure of the natural gas, a desulfurizing portionfor reducing sulfur contained in the natural gas, and a zeoliteabsorbent for removing odorization from the natural gas.

[0052] The water supply portion 6 is provided with a plunger pump thatpumps ion-exchanged water into the reformer 1 and the evaporator 4. Thewater supply portion 6 is provided with a flow rate switch 6 a, whichallows adjustment of the water to be supplied to the reformer 1 and theevaporator 4.

[0053] The control portion 7 is configured to control the material feedportion 5 and the water supply portion 6 so that the amount of feedmaterial and the amount of water are adjustably supplied to the reformer1 and the evaporator 4. The control portion 7 is also configured tocontrol the flow rate switch 6 a of the water supply portion 6 to selectwater destination. The control portion 7 has a temperature dataprocessing portion to recognize a state of the reformer 1 from thetemperature measured by the temperature measuring portion 2, and isconfigured to control the material feed portion 5 and the water supplyportion 6 based on the information obtained in the temperature dataprocessing portion, thereby adjusting supply amount of the feedmaterial, air, and water. The control portion 7 further has a storageportion including a semiconductor (not shown) to store the temperatureof the reformer 1 therein.

[0054] For the purpose of increased energy use efficiency in operationof the system, the hydrogen generation system of this embodiment isoperated in such a manner that the heater 3 is activated to heat thereformer 1, and then, using excess heat after heating of the reformer 1,the evaporator 4 is heated. The reasons for this are as follows: i)Since the steam reforming reaction conducted in the reformer 1 is anendothermic reaction, and for the purpose of high reaction rate, thereformer 1 is required to be kept at a temperature as high as 650 to800° C. when using a hydrocarbon based material and to be kept at atemperature as high as 300° C. or more when using an alcohol basedmaterial, high-quality heat energy derived from the heater 3 isdesirably used with priority in the reformer 1. ii) In steady operationof the system, energy use efficiency in the entire system is desirablyincreased by performing heat recovery efficiently by using the heatenergy derived from the heater 3 to evaporate the water in theevaporator 4.

[0055] However, when heating of the reformer 1 precedes heating of theevaporator 4 as described above, generation of the steam in theevaporator 4 is delayed depending on the configuration of the system,heating conditions, or the like, during start of the system. Under thecondition, sufficient steam is not supplied to the reformer 1, therebycausing the reforming catalyst to be heated excessively. When heatedexcessively, a specific surface area of catalyst and its catalyticactivity are reduced. If the feed material (natural gas) is fed to thehigh-temperature reforming catalyst under the insufficient steamcondition, there is a high possibility that carbon contained in the feedmaterial precipitates. Accordingly, in the hydrogen generation system ofthis embodiment, the steam is generated smoothly as described followingduring the start of the system, thereby reducing a thermal load appliedon the reforming catalyst, which state occurs in the conventionalhydrogen generation system as mentioned previously.

[0056] Hereinafter, a starting operation of the hydrogen generationsystem of this embodiment will be described in conjunction with itseffects.

[0057] First of all, to start the system in a stop state, the heater 3is activated to heat the body of 15 of the system. Here, the reformer 1is heated with priority from the heat from the heater 3. Then, thenatural gas, as the feed material, is fed from the material feed portion5 to the evaporator 4 through the material feed passage 5 a, and isfurther fed to the reformer 1 through the mixed material supply passage16. Meanwhile, the water, which will be converted into the steam to beused in the steam reforming reaction, is supplied from the water supplyportion 6 to the reformer 1. At this time, the flow rate switch 6 aswitches the water supply passage to select either the supply passage 6b to the reformer 1 or the supply passage 6 c to the evaporator 4.

[0058] For example, in the case where, during start of the system (i.e.,in an initial stage of heating), the water is supplied from the watersupply portion 6 to the evaporator 4 through the supply passage 6 c, andthen, in the evaporator 4, the water is evaporated and the resultingsteam and the feed material are supplied to the reformer 1 through themixed material supply passage 16, there is a possibility that apercentage of the feed material (natural gas) is higher than apercentage of the steam in the mixed feed material fed to the reformer1. The reason for this will be described. When the heater 3 is activatedat the start of the system, the heat from the heater 3 is used withpriority to heat the reformer 1 as described above. As a result,temperature increase in the evaporator 4 is delayed according to heatcapacity of the reformer 1 although its state is non-uniform dependingon the size of the system or arrangement of components of the system.That is, the temperature of the evaporator 4 is not yet sufficientlyincreased. In this state, when water is supplied to the reformer 1through the evaporator 4, water is not sufficiently evaporated in theevaporator 4, and thereby sufficient steam is not obtained, so that onlythe natural gas is fed to the reformer 1. Under the condition in whichthe water is insufficiently evaporated, i.e., the condition in whichsufficient steam is not supplied to the reformer 1, if the reformer 1 isheated, thereby causing temperature of the reforming catalyst containedin the reformer 1 to be increased, then the natural gas is thermallydecomposed, and carbon precipitates on the reforming catalyst and insidethe reformer 1. This would lead to degradation of the catalytic activityof the reforming catalyst and clogging in a flow passage inside thereformer 1. In addition, the steam reforming reaction inside thereformer 1 is an endothermic reaction, and therefore, the temperature ofthe reforming catalyst tends to be elevated due to the fact that theheat given by the heater 3 remains unused unless the steam reformingreaction proceeds in the reforming catalyst. As a result, the catalyticactivity would be degraded. Accordingly, in this embodiment, to avoiddegradation of the catalytic activity of the reforming catalyst or thelike, sufficient steam is supplied to the reformer 1 in the initialstage of heating in the following way.

[0059] In this embodiment, since the water supply portion 6 is providedwith the supply passage 6 b to the reformer 1 and the supply passage 6 cto the evaporator 4, the water is supplied to the reformer 1 and theevaporator 4, and the flow rate switch 6 a adjusts the amount of waterto be led to the supply passage 6 b and the amount of the water to beled to the supply passage 6 c. Thus, the amount of water to be suppliedto the reformer 1 and the amount of water to be supplied to theevaporator 4 can be controlled. With this configuration, during a timeperiod just after start of the system when the evaporator 4 is notsufficiently heated and thereby the water is not sufficiently evaporatedin the evaporator 4, the flow rate switch 6 a is adjusted so that thewater is delivered from the water supply portion 6 to the supply passage6 b, and the water is directly supplied to the reformer 1 through thesupply passage 6 b. By doing so, the water is evaporated in the reformer1 which has been heated with priority and thereby has an increasedtemperature. As a result, upon start of the system, the steam exists ina stable condition inside the reformer 1, and therefore, precipitationof carbon due to thermal decomposition of the feed material hardlyoccurs. With an increase in the temperature of the reforming catalyst inthe reformer 1 where the steam and feed material coexist, the steamreforming reaction as the endothermic reaction proceeds on the reformingcatalyst. Thereby, the reforming catalyst is prevented from being heatedexcessively.

[0060] However, when the water is directly supplied to the reformer 1and evaporation of the water (water evaporation reaction) is conductedin the reformer 1 as described above, the heat supplied from the heater3 to the reformer 1 is partially used for the water evaporationreaction. Therefore, in contrast to the case where the heat from theheater 3 is not used for the water evaporation reaction, i.e.,pre-generated steam is directly to the reformer 1, the temperature ofthe reformer 1 is lowered because of the used heat, under the equal heatsupply amount. So, in order to keep the reformer 1 at a temperaturesuitable for the steam reforming reaction, it is necessary to supplymore heat from the heater 3 to the reformer 1 than in the case whereheat is not used for the water evaporation reaction. As should beunderstood from the above, when the water is directly supplied to thereformer 1, heat efficiency of the steam reforming reaction tends to bereduced.

[0061] Accordingly, for the purpose of suppressing such reduction ofheat efficiency, in this embodiment, in the state in which apredetermined time elapses after start of the system and the evaporator4 has been heated sufficiently to allow the water to be sufficientlyevaporated therein (i.e., during steady operation), the flow rate switch6 a is controlled to switch of the supply passage from the supplypassage 6 b to the supply passage 6 c. Then, the water is supplied tothe evaporator 4 through the supply passage 6 c. Such switching isaccomplished by timer-control of the flow rate switch 6 a, which isexecuted by the control portion 7. The water supplied to the evaporator4 is converted into steam through the water evaporation reaction in theevaporator 4. Then, the steam and the feed material are supplied to thereformer 1 through the mixed material supply passage 16. By operatingthe system during steady operation of the system in this manner, in thereformer 1, the heat from the heater 3 is efficiently used for the steamreforming reaction without a loss of heat due to the water evaporationreaction. Also, in the evaporator 4, the steam is generated efficientlyusing the heat from the heater 3.

[0062] Thus, in the system of this embodiment, in the initial stage ofheating, by conducting the water evaporation reaction in the reformer 1,deficiency of steam inside the reformer 1 is avoided and excessiveheating and precipitation of carbons in the reformer 1 are therebyprevented. In addition, during the steady operation of the system, sincethe heat from the heater 3 is effectively used to generate the steam inthe evaporator 4, heat efficiency of the steam reforming reaction in thereformer 1 can be increased. Consequently, it is possible to achieve ahydrogen generation system which can increase heat efficiency and stablygenerate hydrogen.

[0063] The amount of water to be supplied to the reformer 1 in theinitial stage of heating and during the steady operation is preset inview of a reaction temperature in the reformer 1 and use condition suchas catalyst volume. One preferable measure of the amount of water istwice or more of the number of carbon atoms contained in the feedmaterial (natural gas). In this embodiment, for example, the measure is2.5 times.

[0064] With regard to start time of supply of the feed material and thewater during start of the system, the control portion 7 controls thematerial feed portion 5 and the water supply portion 6 based on thetemperature of the reformer 1 which is detected by the temperaturemeasuring portion 2. For example, a reference value is set in atemperature detected by the temperature measuring portion 2, and whenthe detected temperature exceeds the reference value, the controlportion 7 controls the material feed portion 5, the water supply portion6, and the flow rate switch 6 a so that supply of the feed material andsupply of the water are started. Here, the reference value is set to200° C. This can lessen variation in timings for starting supply of thefeed material and the water, and allow the water evaporation to proceedsmoothly and stably in the reformer 1, and excessive heating in thereformer 1 to be effectively prevented. When a large amount of water issupplied to the reformer 1 under a low-temperature condition, a gas flowpassage might be clogged with the water remaining unevaporated in thereformer 1. But, such situation is avoided by supplying the water afterchecking that the temperature of the reformer 1 has exceeded thereference value. It is necessary to determine the reference value basedon correlation between the temperature of the reformer 1 and reactivityof the steam reforming reaction, or correlation between the temperatureof the reformer 1 and an evaporation state of water. Therefore, thereference value varies depending on the size of the system or assumedoperating conditions, and 200° C. is only illustrative. Preferably, alower limit value of the reference value is preset with reference to atemperature at which water is evaporated and a an upper limit valuethereof is present with reference to a heat-resistant temperature of thereforming catalyst.

[0065] In the above configuration, the flow rate switch 6 a isconfigured to switch the water supply passage from the supply passage 6b to the supply passage 6 c by timer control. To execute such timercontrol, time is preset to optimize temperature of the reformingcatalyst and the evaporation state of water, in view of the size of thesystem or the operating condition.

[0066] Alternatively, switching of water supply may be performed by anysuitable methods other than he above timer control. As a modification(another example) of this embodiment, for optimized water evaporation,switching of water supply may be performed based on the temperature ofthe reformer 1. Specifically, a reference value (also referred to as asecond reference value) which is different from the above-identifiedreference value (also referred to as a first reference value) associatedwith start of supply of the feed material and the water, is set in atemperature detected by the measuring portion 2, and based on the secondreference value, the control portion 7 controls the flow rate switch 6a. The second reference value is set based on correlation between thetemperature of the reformer 1 and a heating state of the evaporator 4,and is equal to the temperature of the reformer 1, which corresponds tothe state of the evaporator 4 which has been heated sufficiently toenable water evaporation reaction. For example, the second referencevalue is set to 700° C. The second reference value is suitably presetand varies according to the size of the system or assumed operatingconditions.

[0067] Subsequently, switching operation of the supply passage will bedescribed. First of all, when the temperature detected by the measuringportion 2 has exceeded the second reference value, i.e., the evaporator4 has been heated sufficiently to be suitable for water evaporationreaction, the control portion 7 controls the flow rate switch 6 a toswitch the water supply passage from the supply passage 6 b to thesupply passage 6 c. Thereby, the water, which was directly supplied tothe reformer 1 through the supply passage 6 b, is supplied to thereformer 1 through the supply passage 6 c and the evaporator 4. Thus, byswitching of water supply based on the state of the evaporator 4 judgedfrom the temperature of the reformer 1, switching can smoothly occur. Inaddition, deficiency of steam in the reformer 1 in switching is reliablyavoided.

[0068] While the feed material is fed from the material feed portion 5to the reformer 1 through the evaporator 4, the gas may be directly fedto the reformer 1 without flowing through the evaporator 4. It should beappreciated that, when the feed material is fed through the evaporator4, the gas is preheated by the evaporator 4, and therefore heatefficiency is increased.

[0069] In this embodiment, during start of the system, the reformer 1 isfirst heated and then the feed material and the water are simultaneouslysupplied to reformer 1. Instead, the water may be first supplied to thereformer 1 and then the feed material may be supplied to the same. Also,alternatively, water which would not cause adverse effects, such asclogging of the gas flow passage, may be supplied in advance to a waterevaporation region of the reformer 1 and the evaporator 4, before beingsufficiently heated. Also, in that case, the effects of the presentinvention are obtained. Thus, by supplying the water to the reformer 1or the evaporator 4 in advance, the steam can be smoothly generated inthe initial stage of heating. By doing so, thermal degradation of thereforming catalyst, precipitation of carbons, and the like, which wouldotherwise occur in the initial stage of heating in the reformer 1, canbe effectively avoided.

[0070] In this embodiment, switching of the water supply passage by theflow rate switch 6 a may be controlled in such a manner that the amountof water to be supplied from the water supply portion 6 to the supplypassage 6 b and to the supply passage 6 c is adjusted by, for example,adjusting an operating condition of a feed pump. Alternatively, theswitching may be controlled by adjusting opening and closing ofelectromagnetic valves provided in the passages 6 b and 6 c. Further,alternatively, the switching may be performed stepwise such that theamount of water to be supplied to the reformer 1 and the amount of waterto be supplied to the evaporator 4 are gradually changed. Moreover,alternatively, switching from the reformer 1 to the evaporator 4 may beaccomplished by fully opening and fully closing the electromagneticvalves provided in the passages 6 b and 6 c at a time.

[0071] (Second Embodiment)

[0072] A second embodiment of the present invention will be described.

[0073]FIG. 2 is a view showing a configuration of a hydrogen generationsystem according to the second embodiment of the present invention. Thehydrogen generation system of this embodiment has a configuration almostidentical to that of the system of the first embodiment except that theevaporator 4 is provided with a temperature measuring portion 9 todetect a temperature of the evaporator 4 or a temperature of a gasinside the evaporator 4.

[0074] Since an operation of the system of this embodiment is similar tothat of the first embodiment, its detail will not be further describedand only difference between them will be described. In the system ofthis embodiment with the evaporator 4 provided with the temperaturemeasuring portion 9, a reference value is set in a temperature detectedby the temperature measuring portion 9, and when the detectedtemperature has exceeded the reference value, the flow rate switch 6 aswitches the water destination from the reformer 1 to the evaporator 4in the same manner as described in the first embodiment. The referencevalue is set to, for example, 200° C. in view of a generation state ofthe steam in the evaporator 4 based on operating conditions of thesystem.

[0075] The reference value varies and is therefore suitably setdepending on the size of the system or operating conditions such as theamount of water supply.

[0076] While the heating state of the evaporator 4 is judged indirectlyfrom the temperature of the reformer 1 which is detected by thetemperature measuring portion 2 in the first embodiment, the temperatureof the evaporator 4 is measured directly by using the temperaturemeasuring portion 9. Therefore, water can be supplied at moreappropriate timing to the evaporator 4 which has been heated to besuitable for water evaporation. Therefore, in switching of water supply,the steam is generated smoothly and stably, and water evaporation isoptimized. As a result, deficiency of the steam in the reformer 1 inswitching can be avoided.

[0077] (Third Embodiment)

[0078] A third embodiment of the present invention will be described.

[0079]FIG. 3 is a view showing a configuration of a hydrogen generationsystem according to the third embodiment of the present invention. Thehydrogen generation system of this embodiment has a configuration almostidentical to that of the system of the second embodiment except that theevaporator 4 is provided with an heater 4 a for heating the evaporator 4or a gas inside the evaporator 4. The heater 4 a is comprised of asheath heater which is located on a downstream face of the evaporator 4to allow water supplied from an upstream face side of the evaporator 4to be evaporated in the evaporator 4, although this is not specificallyshown.

[0080] Since an operation of the system of this embodiment is similar tothat of the first embodiment, its detail will not be further describedand only difference between them will be described. Specifically, in thesystem of the present invention, the heater 4 a is activated duringstart of the system to smoothly heat the evaporator 4 to the state inwhich water evaporation can be conducted therein. As mentionedpreviously in the first embodiment, just after start of the system, thetemperature of the evaporator 4 is less likely to be increased andtherefore it takes time to heat the evaporator 4 to the state in whichwater is evaporated therein. But, in this embodiment, the heater 4 a isprovided to directly heat the evaporator 4. This enables water to beevaporated more smoothly in the evaporator 4. Thereby, even when wateris supplied to the evaporator 4 just after start of the system, thesteam is generated smoothly and stably. In accordance with theconfiguration of this embodiment, if water should be supplied only tothe evaporator 4 during start of the system, the steam is generated inthe evaporator 4. Therefore, deficiency of the steam in the reformer 1can be avoided.

[0081] The operation of the heater 4 a is stopped at the time when waterevaporation sufficiently occurs in the evaporator 4 only by heat fromthe heater 3. It is desirable to judge whether or not to stop the heater4 a based on the temperature detected by the temperature measuringportion 2 or the temperature detected by the temperature measuringportion 9. Thereby, water evaporation is optimized with increased heatefficiency. Specifically, a temperature of the reformer 1 or atemperature of the evaporator 4 at which the evaporator 4 can generatesufficient steam is preset as a reference value in the temperaturedetected by the temperature measuring portion 2 or the temperaturedetected by the temperature measuring portion 9. Here, the referencevalue is set to 700° C. in the temperature measuring portion 2. When thedetected temperature has exceeded the reference value, the controlportion 7 stops the heater 4 a. The reference value is suitably setdepending on the size of the system or the operating condition.

[0082] (Fourth Embodiment)

[0083] A fourth embodiment of the present invention will be described.

[0084]FIG. 4 is a view showing a configuration of a hydrogen generationsystem according to the fourth embodiment. The hydrogen generationsystem of this embodiment has a configuration almost identical to thatof the system of the second embodiment except that a vaporizer 10 isprovided at a position in the supply passage 6 c through which water issupplied to the evaporator 4. FIG. 5 is a schematic cross-sectional viewshowing an example of a configuration of the vaporizer 10 of thisembodiment, i.e., a vaporizing unit 10′.

[0085] As shown in FIGS. 4 and 5, in this embodiment, the vaporizingunit 10′ is provided in the supply passage 6 c connecting the watersupply portion 6 to the evaporator 4. The vaporizing unit 10′ has a body10 b having a water inlet 10 g and a steam exit 10 h. The body 10 bcontains an electric heater 10 a such as a sheath heater, a heataccumulator 10 c, a water evaporator 10 d, and an evaporation space 10f. The water inlet 10 g and the steam exit 10 h are each connected tothe supply passage 6 c. The body 10 b is provided with a heataccumulator temperature measuring portion 10 e on an outer wall thereof.

[0086] In the vaporizing unit 10′, the water delivered from the watersupply portion 6 through the supply passage 6 c is introduced into theevaporation space 10 f through the water inlet 10 g. Inside thevaporizing unit 10′, heat derived from the electric heater 10 a is givento water within the evaporation space 10 f through the heat accumulator10 c and the water evaporator 10 d (e.g., porous metal) provided tostabilize water evaporation. The heat causes the water to be vaporizedinto steam. The steam is supplied from the steam exit 10 h to theevaporator 4 through the supply passage 6 c. Here, a temperature of theheat accumulator 10 c is measured by the heat accumulator temperaturemeasuring portion 10 e, and based on the detected temperature, watervaporization is controlled. As a result, the vaporizing unit 10′ canvaporize water stably and efficiently.

[0087] Since an operation of the system of this embodiment provided withthe vaporizer 10 is similar to that of the first embodiment, its detailwill not be further described and only difference between them will bedescribed. In the system of this embodiment during start of the system,the vaporizer 10 (vaporizing unit 10′) is activated as described above,and the steam obtained in the vaporizer 10 is supplied to the evaporator4. As described in the first embodiment, after start of the system, ittakes time for the evaporator 4 to be heated to the state in which wateris evaporated therein. So, by generating the steam in advance in thevaporizer 10 and supplying the steam to the evaporator 4, the steam canbe supplied smoothly and stably from the evaporator 4 to the reformer 1even just after start of the system.

[0088] The operation of the vaporizer 10 is stopped at the time whenwater evaporation sufficiently occurs in the evaporator 4 only from theheat by the heater 3. It is desirable to judge whether or not to stopthe vaporizer 10 based on the temperature detected by the temperaturemeasuring portion 2 or the temperature detected by the temperaturemeasuring portion 9. Thereby, water evaporation is optimized withincreased heat efficiency. Specifically, the temperature of the reformer1 or the temperature of the evaporator 4 at which sufficient steam isgenerated in the evaporator 4 is preset as a reference value in thetemperature detected by the temperature measuring portion 2 or thetemperature detected by the temperature measuring portion 9. It isdesirable to control starting and stopping operations of the vaporizer10 based on the reference value.

[0089] The vaporizer 10 may be always operated, but, considering theenergy consumption necessary for vaporizing water, desirably, theoperation of the vaporizer 10 is stopped and the steam is generated onlyin the evaporator 4 at the time when the evaporator 4 can generate thesteam for itself by the heat from the heater 3. In this case, it isnecessary to configure the supply passage 6 c to allow water to besupplied from the water supply portion 6 to the evaporator 4 withoutbeing affected by the vaporizer 10.

[0090] While the vaporizer 10 is comprised of the vaporizing unit 10′shown in FIG. 5, the configuration of the vaporizer 10 is not intendedto be limited to this. FIGS. 6A and 6B are cross-sectional viewsschematically showing another configuration of the vaporizer 10 for usein the system of this embodiment.

[0091] As shown in FIG. 6A, instead of the vaporizing unit 10′independently provided as shown in FIG. 5, the vaporizer 10 may beconfigured such that a heating source 10 a′ such as an electric heateris outerly fitted onto a pipe forming the supply passage 6 c.Alternatively, as shown in FIG. 6B, the vaporizer 10 may be configuredto have a pipe containing a built-in heating source such that the pipeforming a supply passage 6 c′ has an internal double structure definedby circumferentially extending walls and contain a heating source 10 asuch as an electric heater that surrounds a space as a water flowpassage.

[0092] The heating source for the vaporizer 10 is not intended to belimited to the above electric heating source such as the electricheater, but may be other suitable heating sources, such as heatingsources using combustion heat. For example, the vaporizer 10 may have ageneral burner as the heating source, including a catalyst burner, aflame burner, or the like, which is configured to conduct combustionusing part of an excess hydrogen gas discharged from the destination towhich the hydrogen gas generated in the hydrogen generation system isdelivered (e.g., a fuel cell anode off-gas), or part of the feedmaterial used in the reforming reaction.

[0093] (Fifth Embodiment)

[0094] A fifth embodiment of the present invention will be described.

[0095] A hydrogen generation system of this embodiment has aconfiguration almost identical to that of the first embodiment exceptthat the reformer 1 is provided with a evaporator 1 a. Therefore, adetail of the configuration of the system of this embodiment will not bedescribed and only difference between this system and the system of thefirst embodiment will be described.

[0096]FIG. 7 is a view showing a configuration of the reformer 1according to the fifth embodiment. As shown in FIG. 7, in thisembodiment, the evaporator 1 a is provided between the supply passage 6b and the reformer 1 (more specifically, reforming reaction portion 1 bcontaining a reforming catalyst). The evaporator 1 a is configured toevaporate water supplied through the supply passage 6 b using the heatfrom the heater 3 (FIG. 1) as mentioned later. The evaporator 1 a isconnected to the supply passage 6 b and the mixed material supplypassage 16 and communicates with the reformer 1 through penetratingholes 17. The evaporator 1 a needs to be configured to allow heating ofa reforming catalyst in the reformer 1 to be conducted with priorityduring steady operation of the system and enable stable evaporation ofwater supplied during start of the system. In this embodiment, theevaporator 1 a is disposed to surround an outer periphery of thereforming reaction portion 1 b and to be located upstream of thereforming reaction portion 1 b in the mixed material supply passage 16as seen from the evaporator 4.

[0097] Since an operation of the system of this embodiment is similar tothat of the first embodiment, its detail will not be further describedand only difference between them will be described. Specifically, in thesystem of this embodiment, unlike in the first embodiment in which wateris directly supplied to the reforming reaction portion 1 b through thesupply passage 6 b, water is first supplied from the water supplyportion 6 to the evaporator 1 a through the supply passage 6 b. Then, inthe evaporator 1 a, water is evaporated into steam, which is thensupplied to the reforming reaction portion 1 b through the penetratingholes 17. In this configuration, the reformer 1 has two parts havingdifferent functions, i.e.,the reforming reaction portion 1 b thatcontains reforming catalyst and conducts reforming reaction, and theevaporator 1 a that evaporates water into the steam to be used in thereforming reaction. Therefore, the steam can be generated more stablyjust after start of the system. In addition, during steady operation ofthe system, if water remaining unevaporated in the evaporator 1 shouldbe delivered to the reformer 1, such water is evaporated in theevaporator 1 a and the resulting steam is reliably supplied to thereforming reaction portion 1 b. Consequently, the steam can be suppliedstably with less variation in water evaporation, and thereby thereforming reaction can be stabilized.

[0098] Numerous modifications and alternative embodiments of theinvention will be apparent to those skilled in the art in view of theforegoing description. Accordingly, the description is to be construedas illustrative only, and is provided for the purpose of teaching thoseskilled in the art the best mode of carrying out the invention. Thedetails of the structure and/or function may be varied substantiallywithout departing from the spirit of the invention and all modificationswhich come within the scope of the appended claims are reserved.

What is claimed is:
 1. A hydrogen generation system comprising: areformer for generating a reformed gas that contains hydrogen byreforming reaction from a feed material and steam using a reformingcatalyst; an evaporator for evaporating water into the steam which issupplied to the reformer; a heater for heating the reformer and theevaporator for reforming and evaporation, respectively; a material feedportion for feeding the feed material to the reformer directly orthrough the evaporator; a water supply portion for supplying the water;a first water passage through which the water is supplied from the watersupply portion to the evaporator; and a second water supply passagethrough which the water is supplied from the water supply portion to thereformer.
 2. The hydrogen generation system according to claim 1,wherein upon starting supply of the feed material from the material feedportion to the reformer, the water is supplied from the water supplyportion to the reformer through the second water supply passage, andafter an elapse of a predetermined time after starting the supply, thewater is supplied from the water supply portion to the evaporatorthrough the first water supply passage, and the supply of the water tothe reformer is stopped.
 3. The hydrogen generation system according toclaim 1, wherein the reformer has a reformer temperature measuringportion for detecting a temperature of the reforming catalyst or atemperature of a gas inside the reformer, and based on temperatureinformation detected by the reformer temperature measuring portion,supply of the feed material from the material feed portion and supply ofthe water from the water supply portion are controlled.
 4. The hydrogengeneration system according to claim 3, wherein when the temperaturedetected by the reformer temperature measuring portion is larger than apreset reference value, the water is supplied from the water supplyportion to the reformer through the second water supply passage and thefeed material is fed from the material feed portion to the reformer. 5.The hydrogen generation system according to claim 3, wherein when thetemperature detected by the reformer temperature measuring portion islarger than a preset first reference value, the water is supplied fromthe water supply portion to the reformer through the second water supplypassage and the feed material is fed from the material feed portion tothe reformer, and when the temperature detected by the reformertemperature measuring portion is larger than a preset second referencevalue larger than the first reference value, the water is supplied fromthe water supply portion to the evaporator through the first watersupply passage and the supply of the water to the reformer is stopped.6. The hydrogen generation system according to claim 1, wherein theevaporator has a evaporator temperature measuring portion for detectinga temperature of the evaporator or a temperature of a gas inside theevaporator, and based on temperature information detected by theevaporator temperature measuring portion, supply of the water from thewater supply portion to the reformer and supply of the water from thewater supply portion to the evaporator are controlled.
 7. The hydrogengeneration system according to claim 6, wherein when the temperaturedetected by the evaporator temperature measuring portion is smaller thana preset reference value, the water is supplied from the water supplyportion to the reformer through the second water supply passage, andwhen the temperature detected by the evaporator temperature measuringportion is larger than the reference value, the water is supplied fromthe water supply portion to the evaporator through the first watersupply passage and the supply of the water to the reformer is stopped.8. The hydrogen generation system according to claim 1, wherein theevaporator has a heater for heating the evaporator.
 9. The hydrogengeneration system according to claim 8, wherein the heater of theevaporator is controlled based on a temperature of the reformer or atemperature of the evaporator.
 10. The hydrogen generation systemaccording to claim 9, wherein when the temperature of the reformer orthe temperature of the evaporator is smaller than a preset referencevalue, the water is supplied from the water supply portion to thereformer through the second water supply passage and the heater of theevaporator is operated, and when the temperature of the reformer or thetemperature of the evaporator is larger than the reference value, thewater is supplied from the water supply portion to the evaporatorthrough the first water supply passage and the operation of the heaterof the evaporator is stopped.
 11. The hydrogen generation systemaccording to claim 10, wherein when the temperature of the reformer islarger than a preset first reference value, the feed material is fedfrom the material feed portion to the reformer and the water is suppliedfrom the water supply portion to the reformer through the second watersupply passage, and the heater of the evaporator is operated, and whenthe temperature of the reformer is larger than a preset second referencevalue which is larger than the first reference value, the water issupplied from the water supply portion to the evaporator through thefirst water supply passage and the supply of the water to the reformeris stopped, and the operation of the heater of the evaporator isstopped.
 12. The hydrogen generation system according to claim 1,further comprising: a vaporizer for generating the steam from the water,the steam generated in the vaporizer being supplied to at least one ofthe reformer and the evaporator.
 13. The hydrogen generation systemaccording to claim 12, wherein the vaporizer is controlled based on atemperature of the reformer or a temperature of the evaporator.
 14. Thehydrogen generation system according to claim 13, wherein when thetemperature of the reformer or the temperature of the evaporator islarger than a preset reference value, the water is supplied from thewater supply portion to the evaporator through the first water supplypassage and the operation of the vaporizer is stopped.
 15. The hydrogengeneration system according to claim 14, wherein when the temperature ofthe reformer is larger than a preset first reference value, the feedmaterial is fed from the material feed portion to the reformer, and thevaporizer is operated, and when the temperature of the reformer islarger than a preset second reference value which is larger than thefirst reference value, the water is supplied from the water supplyportion to the evaporator through the first water supply passage and theoperation of the vaporizer is stopped.
 16. The hydrogen generationsystem according to claim 1, wherein the evaporator includes: a firstevaporator placed in contact with the reformer and communicate with thereformer and connected to the water supply portion at least through thesecond water supply passage, the first evaporator being configured toevaporate the water supplied to the reformer at least through the secondwater passage into steam which is supplied to the reformer, and a secondevaporator connected to the water supply portion through the first watersupply passage, the second evaporator being configured to evaporate thewater supplied from the water supply portion into the steam which issupplied to the reformer.
 17. The hydrogen generation system accordingto claim 1, wherein the water supply portion has a water supply switchfor switching of water destination between the reformer and theevaporator.
 18. The hydrogen generation system according to claim 17,wherein the water supply switch is capable of adjusting a flow rate ofthe water to be supplied to the reformer and a flow rate of the water tobe supplied to the evaporator.
 19. The hydrogen generation systemaccording to claim 17, wherein the water supply switch is capable ofswitching of the water supply passage between the first water supplypassage and the second water supply passage.
 20. The hydrogen generationsystem according to claim 1, wherein at a time when supply of the feedmaterial to the reformer starts, at least one of the water and the steamexists in at least one of the reformer and the evaporator.
 21. A fuelcell system comprising: a hydrogen generation system including: areformer for generating a reformed gas that contains hydrogen byreforming reaction from a feed material and steam using a reformingcatalyst; an evaporator for evaporating water into the steam which issupplied to the reformer; a heater for heating the reformer and theevaporator for reforming and evaporation, respectively; a material feedportion for feeding the feed material to the reformer directly orthrough the evaporator; a water supply portion for supplying the water;a first water passage through which the water is supplied from the watersupply portion to the evaporator; and a second water supply passagethrough which the water is supplied from the water supply portion to thereformer; and a fuel cell for generating a power using an oxidizingagent and hydrogen supplied from the hydrogen generation system.